RESUMO
The objective of this work was to evaluate the technical feasibility of using both oil-extracted microalgae (M) and glycerol (G) in co-digestion with chicken litter (CL), thereby improving biochemical methane potential (BMP). Different feedstock ratios of M (0-30%), G (0-3%) and CL (67-100%) were investigated to determine the best co-digestion condition under mesophilic conditions. According to the modified Gompertz model, the best BMP (131.1mLCH4gVSfed-1) was obtained with the triple co-digestion (M:G:CL) in a proportion of 30:3:67. This yielded a methane production rate (µm) of 3.3mLCH4gVSfed-1d-1 and a lag time (λ) of 17.4d. This treatment reduced chemical oxygen demand (COD) by 91.02% and increased the methane yield 15.8% with respect to the CL control.
Assuntos
Glicerol/metabolismo , Metano/biossíntese , Microalgas/metabolismo , Óleos/isolamento & purificação , Eliminação de Resíduos/métodos , Resíduos , Acetatos/metabolismo , Anaerobiose , Animais , Biocombustíveis/análise , Ácido Butírico/metabolismo , Galinhas , Ácidos Graxos Voláteis/análise , Concentração de Íons de Hidrogênio , Modelos Teóricos , Análise de Componente Principal , Propionatos/farmacologiaRESUMO
A strictly anaerobic, moderately thermophilic, sporulating rod, designated strain Lup 33T, was isolated from an upflow anaerobic sludge blanket (UASB) reactor in Mexico. Strain Lup 33T possessed a few laterally inserted flagella, had a DNA G+C content of 32.2 mol % and grew optimally at pH 7.4 and 40 degrees C. Growth was observed at temperatures of up to 50 degrees C and was inhibited in the presence of 5% NaCl. Strain Lup 33T is heterotrophic and utilized some sugars, peptides and various single amino acids. Gelatin and casein were not used as energy sources. It performed the Stickland reaction and reduced elemental sulfur to sulfide. Acetate was the only fatty acid detected from glucose fermentation, whereas acetate together with isobutyrate and isovalerate were found as end products from peptone fermentation. Phylogenetically, strain Lup 33T branched with members of cluster XII of the order Clostridiales, with Clostridium hastiforme as the closest relative (similarity of 93%). On the basis of the phenotypic, genotypic and phylogenetic characteristics of the isolate, it is proposed as a novel species of a new genus, Sporanaerobacter acetigenes gen. nov., sp. nov. The type strain is strain Lup 33T (= DSM 13106T = CIP 106730T).